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  <div class="section" id="frequently-asked-questions-faq">
<h1>1.3. Frequently Asked Questions (FAQ)<a class="headerlink" href="#frequently-asked-questions-faq" title="Permalink to this headline">¶</a></h1>
<p>This is the ever-growing list of answers to commonly asked questions.  Please
feel free to post you question in our <a class="reference external" href="http://sourceforge.net/projects/zbar/forums/forum/1072195">iPhone Developers forum</a> if you do not
find the information you need in this documentation.</p>
<div class="section" id="general">
<h2>1.3.1. General<a class="headerlink" href="#general" title="Permalink to this headline">¶</a></h2>
<dl class="docutils">
<dt>This looks great...  Where can I get it?</dt>
<dd>You can download the latest version of the SDK from
<a class="reference external" href="http://zbar.sf.net/iphone">http://zbar.sf.net/iphone</a></dd>
</dl>
</div>
<div class="section" id="compatibility">
<h2>1.3.2. Compatibility<a class="headerlink" href="#compatibility" title="Permalink to this headline">¶</a></h2>
<dl class="docutils">
<dt>Which iPhone devices does this library support?</dt>
<dd>The library works <em>only</em> with the iPhone 3GS and iPhone 4.</dd>
<dt>Will you make it work with the iPhone 3G?</dt>
<dd><p class="first"><em>No</em> - the 3G it is not supported and is unlikely to ever be supported.</p>
<p class="last">To be fair, you <em>can</em> use the 3G to scan image files, as long as they&#8217;re in
focus (ie, <em>not</em> images taken by the built-in fixed-focus camera).  There
is at least one application that found a use for this...</p>
</dd>
<dt>What target iOS versions does this library work with?</dt>
<dd><p class="first">iOS 4 is fully supported, including the latest video streaming interfaces.
Since Apple has dropped support for earlier versions of iOS on the App
Store, we recommend that you target only iOS 4 for reading barcodes.</p>
<p>iOS 3.1 is also supported, but you will have to resort to manual capture if
you intend to distribute on the App Store.</p>
<p>The library should work all the way back to iOS 3.0, although we no longer
test with it.  For most cases we recommend you use at least iOS 3.1, which
introduced several must-have enhancements for the UIImagePickerController
(ie, <tt class="xref cpp cpp-member docutils literal"><span class="pre">cameraOverlayView</span></tt> and <tt class="docutils literal"><span class="pre">takePicture</span></tt>)</p>
<p>In all cases you will need at least a 4.0 SDK to build.</p>
<p class="last">See <a class="reference internal" href="compat.html"><em>Backward Compatibility</em></a> for details about iOS version fallbacks.</p>
</dd>
<dt>Are any private APIs in use?</dt>
<dd><p class="first">No - the binary release of the SDK does not use any private APIs.</p>
<p>OTOH, if you do not care about private APIs (for instance, you are
targeting AdHoc or enterprise distribution) and you want to enable
automatic capture with iOS 3.1, you can build a version that uses
UIGetScreenImage (which is again a private API).</p>
<p class="last">See <a class="reference internal" href="compat.html"><em>Backward Compatibility</em></a> for details.</p>
</dd>
<dt>Does this support &#8220;automatic&#8221; barcode capture?</dt>
<dd><p class="first">Yes - if you use iOS 4, the default configuration will capture barcodes
automatically from the video stream.</p>
<p class="last">Again, automatic capture is no longer supported with iOS 3.1 for apps
distributed on the App Store.</p>
</dd>
</dl>
</div>
<div class="section" id="building">
<h2>1.3.3. Building<a class="headerlink" href="#building" title="Permalink to this headline">¶</a></h2>
<dl class="docutils">
<dt>I get &#8220;Undefined symbols&#8221; errors when I try to build?</dt>
<dd>Most likely you did not add all of the necessary framework dependencies.
See <a class="reference internal" href="tutorial.html"><em>ZBar SDK Integration Tutorial</em></a> or <a class="reference internal" href="install.html"><em>Installing the SDK</em></a> for the list of frameworks you need
to link against.</dd>
</dl>
</div>
<div class="section" id="licensing">
<h2>1.3.4. Licensing<a class="headerlink" href="#licensing" title="Permalink to this headline">¶</a></h2>
<p>Please refer to <a class="reference internal" href="licensing.html"><em>Licensing the Library</em></a> for questions about licensing.</p>
</div>
<div class="section" id="barcodes">
<h2>1.3.5. Barcodes<a class="headerlink" href="#barcodes" title="Permalink to this headline">¶</a></h2>
<dl class="docutils">
<dt>Why do my UPC barcodes have an extra 0 at the front?</dt>
<dd><p class="first">The <a class="reference external" href="http://wikipedia.org/wiki/UPC-A">UPC-A</a> symbology is the subset of <a class="reference external" href="http://wikipedia.org/wiki/EAN-13">EAN-13</a> that starts with a leading 0.
The ZBar decoder enables only <a class="reference external" href="http://wikipedia.org/wiki/EAN-13">EAN-13</a> by default, so <a class="reference external" href="http://wikipedia.org/wiki/GTIN">GTIN-13</a> product codes
are consistently reported.  You can choose to receive the 12-digit results
instead by explicitly enabling <a class="reference external" href="http://wikipedia.org/wiki/UPC-A">UPC-A</a>.</p>
<p>The <tt class="xref cpp cpp-member docutils literal"><span class="pre">type</span></tt> property of the symbol can be used to see
which type of barcode is reported.</p>
<p class="last">See <a class="reference external" href="http://wikipedia.org/wiki/EAN-13">EAN-13</a> and <a class="reference external" href="http://wikipedia.org/wiki/UPC-A">UPC-A</a> for more information.</p>
</dd>
<dt>Why does my UPC-E (short version) barcode data look completely wrong?</dt>
<dd><p class="first"><a class="reference external" href="http://wikipedia.org/wiki/UPC-E#Zero-compressed_UPC-E">UPC-E</a> is a &#8220;zero compressed&#8221; version of <a class="reference external" href="http://wikipedia.org/wiki/UPC-A">UPC-A</a>; certain of the zeros are
removed from the <a class="reference external" href="http://wikipedia.org/wiki/UPC-A">UPC-A</a> data to generate the <a class="reference external" href="http://wikipedia.org/wiki/UPC-E#Zero-compressed_UPC-E">UPC-E</a> barcode.  The ZBar
decoder <em>expands</em> this compression by default, again to consistently report
<a class="reference external" href="http://wikipedia.org/wiki/GTIN">GTIN-13</a> product codes.  You can choose to receive the compressed 8-digit
results instead by explicitly enabling <a class="reference external" href="http://wikipedia.org/wiki/UPC-E#Zero-compressed_UPC-E">UPC-E</a>.</p>
<p>The <tt class="xref cpp cpp-member docutils literal"><span class="pre">type</span></tt> property of the symbol can be used to see
which type of barcode is reported.</p>
<p class="last">See <a class="reference external" href="http://wikipedia.org/wiki/UPC-E#Zero-compressed_UPC-E">UPC-E</a> for more information.</p>
</dd>
</dl>
</div>
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  <h3><a href="index.html">Table Of Contents</a></h3>
  <ul>
<li><a class="reference internal" href="#">1.3. Frequently Asked Questions (FAQ)</a><ul>
<li><a class="reference internal" href="#general">1.3.1. General</a></li>
<li><a class="reference internal" href="#compatibility">1.3.2. Compatibility</a></li>
<li><a class="reference internal" href="#building">1.3.3. Building</a></li>
<li><a class="reference internal" href="#licensing">1.3.4. Licensing</a></li>
<li><a class="reference internal" href="#barcodes">1.3.5. Barcodes</a></li>
</ul>
</li>
</ul>

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